Distributive refrigerating evaporator



B. F. KUBAUGH Aug. 1, 1933.

DI STRIBUTIVE REFRIGERAITING EVAPORATOR Filed Feb. 4, 1953 3 Sheets-Sheet l gwmntoz BENJAMIN E KUBAUGH Aug. 1, 1933. F KUBAUGH 1,920,570

DI STRIBUTIVE REFRIGERATING 'EVAPORATOR Filed Feb. 4, 1933 3 Sheets-Sheet 2 Big-4- BENJAMIN F KUBA-UGH Aug 1, 1933. B. F. KUBAUGH DISTRIBUTIVE REFRIGERATING EVAPORATOR Filed Feb. 4, 1953 3 Sheets-Sheet 3 gwoeyflov .BEM/A M/N E 11 USA I/GH OIL LEVEL.

Patented Aug. 1, 1933 UNITED STATES DISTRIBUTIVE REFRIGERATING EVAPO- RATOR Benjamin F. Kubaugh, Louisville, Ky., assignor to Henry Vogt Machine 00., Louisville, Ky., a Corporation of Kentucky Application February 4,

14 Claims.

This invention relates to means and the method for the distribution of liquid refrigerant serially through the several super-posed limbs of the evaporating unit of a refrigeration system,

in such manner as to supply and maintain a volume'of liquid refrigerant in each limb less than the entire capacity of the limb, whereby change of state with consequent temperature drop takes place independently in each limb.

One of the objects of the invention is to obtain increased efliciency of operation in apparatus of the type described by avoiding sources of back pressure which if present might impede the free expansion of the refrigerant. The invention provides for example for the distribution. of the liquid refrigerant and the drawing away of the expanded gas by separate conduits, and in the case of the expanded gas, by providing branch conduits individual to the several levels or stages of the evaporator for conducting away the gas.

The invention also provides for the maintenance of a constant level of liquid refrigerant in the several limbs regardless of the rapidity of evaporation, so that the area of the surface con tacted by the liquid refrigerant shall not diminish, and the absorptive efficiency of the evaporator be thereby impaired.

Another object of the invention is to completely surround the fluid to be refrigerated with the walls of the evaporator, and to conduct said fluid through the evaporator contra-flow with respect to the direction of distribution of the liquid refrigerant.

Still another object of the invention is to provide conveyors within the several limbs of the evaporator functioning not only as pumps for conducting the refrigerated fluid, but also to prevent the deposition of or effect the removal 'of sludge or other matter which would deposit upon the walls of the conduit and impair the heat exchanging efliciency of the walls of the said conduit.

Another object of the invention is the provision of improved driving means for the several conveyors.

Other objects of the invention will appear as the following description of a preferred and practical embodiment thereof proceeds. V

50 In the drawings which accompany and form a part of the following specification and throughout the several figures of which the same characters of references have been employed to designate identical parts:

Figure l is a side elevation of an evaporator embodying the features of the present invention, intermediate portions being broken away;

Figure 2 is a plan view, one end being shown in section to disclose the conveyors;

Figure 3 is a view in detail showing in section 1933. Serial No. 655,267

the connections of the liquid conduit with the limbs of adjacent tiers;

Figure 4 is an end elevation;

Figure 5 is a section taken along the line 55 of Figure 1;

Figure 6 is a vertical section through the lower part of the driving gear casing, showing the submerged oil pump and connections;

Figure 7 is a side elevation of a modified form of the invention, parts being broken away;

Figure 8 is a plan view of the modified form shown in Figure 7, partly in section;

Figure 9 is a section taken on the line 99 of Figure 7; and

Figure 10 is a transverse section through the overflow conduit shown in Figure 3, disclosing the weir.

Referring now in detail to that form of the invention shown in Figures 1 to '7, inclusive, the numeral 1 represents in general an evaporator of the coil type in which the limbs of the coil are arranged in superposed tanks and substantially horizontal. The coil is constituted by a conduit 2 through which the fluid to be chilled or more intensely refrigerated is adapted to be pumped. In the present embodiment of the invention as shown in Figure 2, each tier of the coil. is constituted by a bank of two limbs 3 and 4, although it is to be understood that the invention is not confined to this number, but may include any number of limbs to a bank. The inlet 5 of the conduit 2 is preferably at the bottom of the coil and the liquid entering the coil flows horizontally to the right through the lowermost limb, then by way of the return bend 6 through the rearward limb of the lowermost tier, then upwardly through the manifold 7 into the rear limb of the second tier, then by way of a similar rear bend 4 into the forward limb of the second tier, upwardly by way of the manifold 8 into the front limb of the third tier and so on, until the top of the coil is reached, the liquid discharging from the outlet 9.

The fluid to be refrigerated is impelled through the coil by conveyors l0 and 11 individual to the conduits and having vanes 12 which preferably approach in such proximity to the inner walls of said conduits as to sweep therefrom any matter depositing or having the tendency to deposit upon the walls of said conduits. In this manner the heat exchanging efficiency of the conduits is maintained at the maximum.

The return bends 6 as well as the manifolds '7 and 8 are each provided with bearing apertures 13 and 14 through which pass shafts 15 extending axially of the several limbs and being furnished at the ends with stufling glands 16, in customary manner. The ends of all of the shafts 15 on one side of the coil extend through suitable bearings in a gear casing 17, the ends of said shaft within said casing having worm gears 18 affixed thereto, said worm gears beind disposed in pairs as shown in Figures 2 and 6 with a vertical shaft 19 arising between said pairs and having worms 20, each worm being operatively enmeshed with the gears of a pair. The shaft 19 is suitably driven, as by an electric motor 21 supported by a bracket 22 above the coil.

The lower portion of the gear casing 17 functions as a sump in which oil is maintained, and in the sump submerged in the oil is an oil pump 23 taking oil from the sump and delivering it through a conduit 24 to bearings 25 in which the shaft 19 is journalled.

By this means positive pressure lubrication is provided for the driving mechanism.

Throughout the major portion of their length, that is to say, between the return connections at each end, the limbs 3 and 4 are jacketed, being each surrounded by a conduit 26 of relatively large diameter, leaving an intervening space 27 for receiving the refrigerant.

Since it is designed to have the refrigerant stand at a constant level in each of the jackets, the jackets of adjacent tiers are inter-connected by a liquid refrigerant supply conduit 28 connected to the jacket of the upper tier nearthe top and to the jacket of the next tier below at an intermediate point below the level at which the liquid refrigerant is designed to stand. The said lower tier is in turn connected near the top to the conduit next below at an intermediate portion of the latter by the liquid refrigerant supply conduit 29, and. so on down to the lowermost tier. A dam or weir 43 extends across the lower parts of the upper ends of the conduits 28 and 29 adjacent their points of communication with the upper parts of the respective jackets, determining the refrigerant level in said jackets. The conduits are, in the interest of symmetry, arranged alternatingly on opposite sides of the coil.

Liquid refrigerant is conducted from the condenser of a refrigeration system, not shown, simultaneously into the upper part of both of the limbs of the uppermost tier by a pipe 30 which opens into a distributing block 31 having the jacket space 32 common to the refrigerant chambers of both limbs. The liquid refrigerant fills the jackets of the upper tier to a level determined by the weirs 43, the conduit 28 acting as an overflow pipe and then conveys the surplus refrigerant to the jacket of the limb next below, the limbs of this tier being connected by a distributing block 31 and so on to the lower portion of the coil.-

The rate at which the liquid refrigerant is supplied is determined by the rate of evaporation in the several limbs and may be controlled in any suitable manner. It may even be controlled manually. However, it is preferred to provide some means for automatic control and this is indicated at 32' in Figures 1 and 2 in the form of a float chamber controlling a valve 33 in the pipe 30. The level of liquid in the float chamber, to which the float is responsive, is balanced by means of the conduits 34 and 35, the former of which taps the jacket of the lowermost tier below the normal liquid level therein and the uppermost of which taps the jacket of any of the tiers, for example, the next above as shown, above the normal liquid level therein.

It is apparent that the level of liquid refrigerant in each of the jackets stands at a deter mined level below the top of said jackets leaving a gas space for the expansion of the refrigerant as it changes its state in absorbing heat from the liquid to be chilled. In order to prevent the accumulation of any decided pressure in the gas spaces of the several jackets which would tend to inhibit the full expansion of said gases and thereby to reduce the value of the temperature drop upon which the cooling eificiency depends, means are provided for taking away the gases as they are expanded, individual with respect to the several jackets. Said means comprises a stack 36 connected to the low side of the refrigerating machine, not shown, into which the inclined gas conduits 37 debouch communicating with the upper parts of the distributing blocks 31.

' It is obvious from the above construction that regardless of the demands made upon the refrigerant in each of the limbs or tiers of limbs or the activity of ebulition in each, the liquid refrigerant will stand at a constant determined level. This is most important from the standpoint of refrigerative efliciency, for the liquid refrigerant has many times the absorptive capacity as the refrigerant in gaseous form, and the refrigerative capacity of the coil or any limb thereof is much greater than in systems heretofore known, in which the faster the rate of ebulition,

the lower the level of liquid refrigerant sinks in the evaporator. The horizontal position of the several limbs assures the gaseous refrigerant from the necessity of displacing any of the liquid in finding its way back to the low side of the refrigerating machine, this factor together with the individual drawing off of the expanded gases from the several limbs assuring the maximum expansion of the refrigerant with consequent maximum temperature drop.

The liquid to be refrigerated, passes through the conduit 2 in contra-flow direction to that of the liquid refrigerant. While this is not so important in a system in which the refrigerant changes its state independently and individually in each of the limbs of the coil, yet it gains whatever advantage there may be in the temperature differential between the incoming liquid refrigerant ar. 1 the incoming liquid to be cooled.

A modified form of the invention is disclosed in Figures 7, 8 and 9 in which the expanded gaseous refrigerant is not collected from the distributing blocks 31, but by gas manifolds 38 extending longitudinally of and slightly above the several tiers and connected preferably at a plurality of points with gas spaces within the several jackets by branch conduits 39 and 40. These manifolds discharge into a stack 41 conveniently located. In this form of the invention, the liquid refrigerant is admitted to the top of one of the jackets of the uppermost tier by a suitable connection 42 and the distributing blocks 31 function only in distributing the liquid refrigerant be- ,tween the limbs which constitute one tier of bank.

What I claim is:

1. Refrigerating evaporator comprising a conduit arranged serially in superposed tiers, constituted by substantially horizontal limbs with end connections, jackets individual to said limbs and forming therewith evaporator chambers, means for supplying liquid'refrigerant serially to said chambers beginning with the uppermost chamber, said means comprising in part, conduits interconnecting said chambers and arranged to determine a liquid level in each of said chambers, and means individual to each chamber for conducting away the expanded gas originating in each chamber.

2. Refrigerating evaporator comprising means forming a plurality of evaporation chambers arranged substantially horizontally in superposed tiers, means for supplying liquid refrigerant serially to said chambers beginning at the uppermost chamber, said means including overflow conduits from one chamber to the next below, each connected at an intermediate point to the chamber from which it emanates, said point determining the liquid level, conduits individual to each chamber communicating with said chambers at points above the liquid level therein, a stack into which said conduits debouch, and a conduit for conveying fluid to be cooled, passing serially through said chambers.

3. Refrigerating evaporator as claimed in claim 2, the conduit for conveying the fluid to be refrigerated comprising substantially horizontal limbs extending lengthwise throughout said chambers, conveyors in said limbs and means for driving said conveyors.

4. Refrigerating evaporator as claimed in claim 2, the conduit for the liquid to be refrigerated including substantially horizontal limbs extending through said chambers, conveyors in said limbs, and driving means therefor comprising gears operatively connected to said conveyors, a substantially vertical shaft, means on said shaft inter-meshing with the gears of the several conveyors, and a motor for driving said shaft.

5. Refrigerating evaporator as claimed in claim 2, including means responsive to the liquid level in the lowermost tier for controlling the supply of liquid refrigerant to said evaporator.

6. Refrigerating evaporator comprising means forming a plurality of evaporating chambers arranged substantially horizontally in superposed tiers and a plurality in each tier in side by side relation, a distributing block providing a refrigerant passage common to the chambers of a tier, a block being provided for each tier, means for supplying liquid refrigerant to the refrigerating chambers of each tier, and serially with respect to said tiers, said supply means comprising a conduit communicating with the distributing block of the uppermost tier, overflow conduits interconnecting chambers of adjacent tiers, each being connected to the chamber fromwhich it emanates, and an intermediate point, said points determining the liquid level within said chambers, conduits individual to the chambers communicating therewith at points above the liquid level therein for conducting away the expanded gases originating in the several chambers, and a conduit for conducting fluid to be cooled, including substantially parallel limbs extending serially through said chambers.

'7. Refrigerating evaporator comprising means forming a plurality of evaporating chambers arranged substantially horizontally in superposed tiers, and a plurality in each tier in side by side relation, means for distributing liquid refrigerant among the chambers of a tier, said means being duplicated for each tier, means for supplying liquid refrigerant to the evaporating chambers of each tier and serially with respect to said tiers, said supply means comprising a conduit communicating with a chamber of the uppermost tier, overflow conduits interconnecting chambers of adjacent tiers, each being connected to the chamber from which it emanates at an intermediate point in the height of said chambers, said points determining the liquid level within said chambers, conduits individual to the chambers communicating therewith at points above the liquid level therein for conducting away the expanded gases originating in the several chambers, and a conduit for conducting fluid to be cooled including substantially parallel limbs, extending serially through said chambers.

8. Refrigerating evaporator as claimed in claim 7, including a stack into which the gas conducting conduits discharge.

9. Refrigerating evaporator as claimed in claim '7, including conveyors extending through the several limbs, driving gears arranged substantially in a vertical plane and operatively connected to said conveyors, a substantially vertical drive shaft arranged between adjacent gears. worms on said shaft in mesh with adjacent gears and a motor for driving said shaft.

10. Refrigerating evaporator as claimed in claim 7, including a stack into which the gas conducting conduits individually discharge.

11. Refrigerating evaporator comprising means forming a plurality of evaporating chambers arranged substantially horizontally in superposed tiers, and a plurality in each tier in side by side relation, means for distributing liquid refrigerant among the chambers of a tier, said means being duplicated for each tier, means for supplying liquid refrigerant to the evaporating chambers of each tier and serially with respect to said tiers, said supply means comprising a conduit communicating with a chamber of the uppermost tier, overflow conduits interconnecting chambers of adjacent tiers, each being connected to the chamber from which it emanates at an intermediate point in the height of said chambers, said points determining the liquid level within said chambers, .conduits individual to the chambers communicating therewith at points above the liquid level therein and adapted to be connected to the low pressure side of a refrigeration system for distributively imposing vacuum upon the several chambers for individually conducting away the expanded gases, and a conduit for conducting fluid to be cooled, extending serially through said chambers.

12. Refrigerating evaporator as claimed in claim 7, including conveyors extending through the several limbs, driving gears arranged substantially in a vertical plane and operatively connected to said conveyors, lip-standing drive shaft arranged between adjacent gears, worms on said shaft in mesh with adjacent gears, means for driving said shaft, a casing enclosing said gears and shaft having the bottom portion constituting a sump and a submerged oil pump in said sump delivering oil to the bearings of said shaft.

13. Refrigerating evaporator as claimed in claim 7, including conveyors extending through said limbs for impelling the fluid to be cooled in a direction contra-flow to the liquid refrigerant. 14. Refrigerating evaporator comprising a conduit arranged serially in superposed tiers,

BENJAMIN F. KU' BA'UGH. 

